Door hinges for vehicles incorporating retention devices are currently known, which retention devices allow the vehicle door to be stably released in one or several preset open positions, preventing the door form being prematurely and automatically closed in an unwanted manner.
By way of example, patent document EP1056916 describes a hinge incorporating a check mechanism for the purpose of providing controlled angular positions in which the hinge leaves forming the actual hinge are maintained such that the door can be released in the desired angular positions. To that end, a check body is provided having a plurality of check members which are pushed radially outwards to make contact with a surrounding check reaction member. The check body is preferably integral with a hinge leaf whereas the check reaction member is integral with the other hinge leaf, such that the rotation of the hinge leaves in relation to one another makes the check body rotate in relation to the check reaction member. The check members are ball-shaped, and the check reaction member has an inner annular face provided with a series of recesses in correspondence with the number of balls of the check body.
Patent document DE 19953077 describes a mechanical alternative for providing a hinge with multiple locking positions according to respective angular positions adopted by the hinge leaves in relation to one another. To that end, the check body is forced by elastic means to remain supported against the rotating surface of the pin of the hinge, which is integral with the mobile hinge leaf, the circumferential contour of which is suitably profiled or even beveled in order to achieve a continuous check effect between the hinge leaves when the pin of the hinge rotates about the hinge axis, and a locking in the angular positions in which the check body can be stably supported against the contour of the pin of the hinge.
Although the described embodiments allow the locking of the door in different angular positions, said locking positions are preset, therefore the door is not locked in any angular position chosen by a user. These designs lack a hinge incorporating a check device suitable for achieving a locking effect, or a retention effect, without the jerking of the door, such that from any one position of the door, the user, after overcoming an initial predetermined force for commencing the rotational movement of the door in either direction, can move the door to another position of interest and release it, the door being automatically retained again, maintaining the position in which it has been released.
Patent document DE 4406824 describes a door hinge for a motor vehicle with an integrated check and locking function which, in order to achieve a continuous check and a locking without the jerking of the vehicle door, proposes fixing the pin of the hinge in an anti-rotational manner in the support eye of a first hinge half and providing it with at least one radially upward wedge-shaped surface in its entire length in which it must be supported for its movement, and arranging opposite to this wedge surface at least one radially upward wedge surface in the inner perimeter of the borehole of the respective support eye of the second hinge half.
One of the drawbacks of this embodiment is that the opening movement of the door is continuously checked, this check furthermore increasing as the opening angle of the door increases.